The invention relates to a device for sealing the tap hole of a tiltable converter with a sealing plug consisting of a front metal plate which points towards the inside of the converter and melts on impact by liquid steel and a setting tool via which the sealing plug can be inserted into the tap hole and is deformable therein against the wall thereof, the sealing plug having a cylindrical plastic core covered by the front metal plate and a base plate, which are connected displaceably with respect to one another to the setting tool.
Tiltable converters have, in a suitable place in the converter wall above the tank level, a discharge orifice or a tap hole for conveying the liquid steel into the tapping ladle. For emptying, the converter is tipped into such a position that the steel flows through the tap hole into the attached ladle. As specifically lighter slag of varying viscosity always floats on the molten metal, during the tipping process this slag inevitably reaches the tap hole first and thus fairly large amounts of flush slag reach the tapping ladle. For numerous subsequent metallurgical processes the presence of oxygen-rich slag frequently enriched with phosphorus or sulphur is a considerable disadvantage. There is therefore a demand for conveying the converter steel into the tapping ladle with as little slag as possible. A sealing plug for this purpose is known from EP 0 635 071, in which the front metal plate is designed to pass into a funnel-shaped channel which intersects the sealing plug and core and is designed to receive a drawing claw acting on the front metal plate. The sealing plug is pushed so far into the converter wall that with its front metal plate it is positioned approximately in alignment with the inside of the converter and is then set by pulling the claw. The front metal plate passes into a funnel-shaped channel, which intersects the sealing plug, so the fixing of the plug actually does take place on the inside of the converter and not on its outer wall. Once the sealing plug is correspondingly set, the front metal plate fuses and neither slag nor other parts can flow out through the tap hole. In fact the converter can be tipped, the front metal plate and also the funnel-shaped channel now melting on contact with the liquid steel and the steel being able to flow specifically into the ladle through the funnel-shaped channel. A sealing plug of this kind consists of refractory material, primarily aluminosilicate, bonding clay, water and mineral oil.
This gives rise to problems with regard to ease of handling. This is due on the one hand to the great weight of the sealing plug, and on the other hand to a high water consumption caused by using clay a s bonding agent, as well as, in particular, to the extremely rigid design and the associated difficult deformation of the sealing plug when it is placed into the converter hole.